1. Field of the Invention
The field of the present invention is processes for measuring an unbalance of an outer member of a torque converter which transmits a torque from an internal combustion engine to a member to be driven, and processes for correcting such unbalance.
2. Description of the Prior Art
In the conventional measurement and correction of an unbalance of a torque converter, it is a practice to set, in a measuring device, a torque converter comprising an outer member comprised of a pump impeller and an input case, and an inner member assembled within the outer member and comprised of a turbine wheel and a stator wheel, to rotate the outer and inner members in unison to measure a total unbalance of the members, and to correct such unbalance by fixing a balance weight to a portion of the outer member on the basis of the result of the measurement (for example, see Japanese Patent Application Laid-open Nos. 65660/84 and 40829/88).
In the process for measurement of the total unbalance of the outer and inner members as in the prior art, however, it is impossible to accurately measure an unbalance of the outer member independently. This is not suitable for an actual service, because the outer and inner members are rotated independently in a state in which the torque converter is in actual service. Consequently, there is a possibility that if a balance weight for correcting the unbalance is attached to the outer member, the balanced condition may be deteriorated.
In the actual service state of the torque converter, oil is filled within the outer member, so that a torque is transmitted from the outer member to the inner member by virtue of such oil. In the above conventional unbalance measuring process, the unbalance is measured in a condition of no oil filled. For this reason, there is a possibility that if the oil is filled into the outer member in the service state, the balanced condition once reached is deteriorated again by the filled oil due to a circumferential unevenness of the shape of an inner surface of the outer member.
In addition, in the prior art, a balance weight is attached by a padding in a seam-welding and hence, not only is it possible that a casing of the torque converter may be locally heated by a seam-welding torch, so that a strain may be produced in the casing, but also it is difficult to provide a padding of a correct amount due to an instability of welding conditions. Moreover, there is also another problem that a working environment is deteriorated by a torch spark.